Diagnostic certainty is a component of all cases and reflects how well the diagnosis has been established. It ranges from "Possible" to "Certain," and it is very important that the diagnostic certainty is not overstated. Doing so only reduces the utility of the Radiopaedia case library and undermines your credibility as a contributor.
Please be pedantic and skeptical of your cases and strive to establish the diagnosis with supporting information. Please see this article for examples.
On this page:
Which diagnostic certainly level applies?
It is challenging to have a dogmatic definition for each level (see below), as this largely depends on the case. A good rule of thumb is to ask yourself this:
"Would a pedantic, high-end peer-reviewed journal accept the diagnosis if you submitted it as a case report?"
In other words, would a cynical and skeptical third party agree that there was no doubt about the diagnosis? Only if your honest answer is "yes" then, and only then, can the diagnosis be considered "Certain". This is especially true for rare, atypical or generally unusual cases. Remembering a saying popularized by Carl Sagan 3:
"Extraordinary claims require extraordinary evidence."
A compelling case must be mounted before a "Certain" or "Almost certain" diagnostic certainty is accepted. In such instances, it will require histology reports or slides, operative photos, etc. Well-established diagnostic criteria exist for many conditions (e.g. Boston criteria 2.0 for cerebral amyloid angiopathy) and these should be followed to set the diagnostic certainty.
And remember, just because you feel certain does not mean you are right. This is particularly the case if you are straying outside of your comfort zone (you are relatively junior, an unusual case, it is outside of your area of expertise, etc). Whatever you do, don't forget the Dunning-Kruger effect 1,2, which is all too alive and well in medicine.
Where is diagnostic certainty located?
The user interface to set diagnostic certainty is visible immediately below the case title in the text edit mode. It comprises a slider, with descriptions of each state.
The status of cases is indicated with a colored dot (see below).
Diagnostic certainty levels
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Possible (red dot)
the preferred diagnosis (reflected in the case title) is one of a number of possible diagnoses; to be eligible for publication, a robust case discussion is required including why the preferred diagnosis is favored
cases with words such as suspicious, suggestive, concerning, and worrisome usually indicates the case needs a "Possible" diagnostic certainty
cases like this are only sometimes worthwhile, but often they are not due to limited educational value
be prepared for your case to be rejected for publication; that's ok, you can always keep it as one of your unlisted cases
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Probable (orange dot)
the preferred diagnosis is most likely (>90% certain) than any alternative, but the diagnosis has not been established; a robust case discussion is required including why the preferred diagnosis is favored
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Almost certain (yellow dot)
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confirmed diagnosis without substantiated evidence
the case was collected some time ago and have included "path proven" in the description but not the actual histology report
a secondary source states the diagnosis (e.g. the referral, or the treating unit or a colleague tells you the result of a biopsy) but you cannot upload the histology report
histopathology (or other substantiating evidence) is feasible but not routinely obtained
imaging is near pathognomonic (99% certain) but it is conceivable that an unusual-appearing other entity could have similar appearances
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Certain (green dot)
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confirmed diagnosis with substantiated evidence
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clinical, surgical and/or pathological proof directly obtained from a primary source by the author (e.g. histology report/slides, diagnostic laboratory test/values) and, where appropriate, included in the case
NB only English-language substantiating evidence is accepted (translations of non-English language evidence is acceptable)
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unequivocal or pathognomonic imaging appearance, i.e. 100% specific findings with no differential diagnosis
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Not applicable (no dot)
the images are not of a patient with a particular diagnosis
e.g. normal scan for teaching purposes, diagrams, illustrations, flow charts
How diagnostic certainty is used
The diagnostic certainty of a case has many implications and functions.
Firstly it has a strong influence on case completeness, and therefore when sorting search results by case completeness, cases with high diagnostic certainty will be favored. Similarly, these cases will be more frequently shown in quiz mode.
Secondly, search results will show the diagnostic certainty level as a colored dot (matching the slider).
Thirdly, search results may be filtered to only show cases of a minimum diagnostic (e.g. "Almost certain").
NB: it is likely that in the future that "Possible" and "Probable" cases will be filtered from search results.